Conventional imager technologies use quantum and analog detectors, which are complicated to design, build and contain inherent fabrication and performance problems that are difficult and expensive to resolve. These detectors can only detect a small segment of the IR spectrum, either 4 μm or 10 μm (mid or far IR respectively), which is dependent on the detector material selected, the detector design and size. Some disadvantages and limitations of current IR technology are as follows.
The quantum semiconductor technologies have highly complex intricate structures. For example, each pixel has a multitude of nano-sized structures, which makes them difficult to fabricate, and expensive to produce. Moreover, multiple stages contribute noise which limits performance, and improving performance is complex and redesigns are expensive. The complexity requires high-end fabrication facilities and foundries. All these factors contribute to the high cost of such imagers. Furthermore, conventional imager designs are limited to one narrow segment of the IR spectrum, either 4μ or 10μ individually. The analog signals generated by conventional imager designs must be converted to a digital signal (via A/D conversion) before the signal is made into a video image. The instability and noise of analog systems is a significant problem and limits imager performance.